Rosemary Sauce For Roast Venison

Our answer

Nigella's Roast Venison Fillet (from HOW TO EAT) is an elegant dinner dish that is served with a red wine and rosemary sauce and a home-made spiced apple sauce. The rosemary sauce is made from stock and red wine that are cooked together with a mirepoix and then reduced. Cold cubes of butter are whisked into the sauce just before it is served.

The technique of whisking cold butter into a hot sauce, called "mounting with butter", gives a glossy and rich sauce. You should use unsalted butter as salted butter will affect the seasoning and taste of the sauce and a larger saucepan makes it easier to whisk the butter in vigorously. It does need to be done at the last minute, which means a double quantity of sauce will take longer to finish. It is possible that you will not need the full double quantity of butter to finish the sauce. We would suggest that you have the full quantity of butter ready, and then just whisk in enough until you are happy with the appearance and taste of the sauce.